Kensal Rise library was emptied of its books and stripped of the plaque commemorating its opening 112 years ago by Mark Twain in the early hours of Tuesday morning.

Residents who for more than a year campaigned to keep the library open were alerted in the middle of the night that Brent council workers, backed up by police, were stripping the branch of books, furniture, murals painted in the 1930s and the plaque marking the opening in 1900 by Twain. The move follows the council's failed attempt to clear the library earlier this month, when they were stopped from removing books by protesters.

"We were phoned by a local person about 2.30am so went there but there were so many police officers and security and workers everywhere that we were never going to be able to stop them," said Margaret Bailey, a resident. "People are so angry."

Local people, backed by literary names, including Philip Pullman and Alan Bennett, have challenged the decision to close six libraries in the north-west London borough at the high court and supreme court, but were told in February no further appeal would be heard. They are now hoping to run the Kensal Rise branch themselves as a volunteer facility, and pledged this morning that the removal of books from the library would not stop them.

"The cowardice of Brent's Labour council in stripping Kensal Rise library, and the philistinism of unscrewing the brass plaque remembering Mark Twain from its wall, in the middle of the night, would horrify anyone who still recalls Labour's founding mission to share education, knowledge and hope with the people. We will continue to fight for our library," said the author Maggie Gee, vice-president of the Royal Society of Literature.

The playwright Michael Frayn also condemned the move. "They took the books out and the plaque down? So the library is now an unlibrary, in the way that people became unpersons in the darkest days of the Soviet Union. I hope they took the titles of the books off as well. Removing unbooks from an unlibrary – who could possibly object?"

The biographer Sir Michael Holroyd said: "The wanton destruction of the Kensal Rise Library – its books removed, its history erased – is a gross act of philistinism which will bring lasting shame to all involved."

The leader of Brent council, Mohammed Butt, told campaigners he did not order the overnight removals and was not informed the clearance was happening until a couple of hours before council workers moved in.

"The decision to empty the building had been made before I took over the leadership and the go ahead was made by the police at that time on the basis of public safety concerns," he said. He added that his IT system had failed at home and that he had not found out about the removal until midnight last night.

But he stood by the decision to remove the items, saying they had been left in the building for months and would have begun to deteriorate had they remained.

He said the council's solicitors and those acting for All Souls College, Oxford, said the library building had now reverted to the college. He hoped All Souls would return the building to the use for which it was intended.

"They started it out as a community reading room and I think they've got it in their gift to give – and I think they will – that building back to the community," he said.

He told a group of angry protesters outside the library that he would do his best to help them, but stressed that the building belonged to the Oxford college now, adding: "I can't guarantee anything."